Flow‐induced tones in side branch pipe resonators

Shear Laver Coupling with Side-branch Resonators

High velocity flow past the junction of a side branch with a pipe can result in the excitation of depth-mode standing waves in the branch. The shear layer separating the main stream flow and the cavity provides coupling between the driving and the driven fl ow. Photographi c evi dence i ndi cates that 1arge scale vortex structures develop at the shear layer. The vortex formation process involve...

Application of resonators and a side branch duct with an expansion chamber for broad band noise control

One way of attenuating broad band noise that propagates through ducts or pipe systems is to use one or more reactive-type acoustic components, each of which is specifically designed for optimal performance at a particular frequency range. This paper uses the transfer matrix method for predicting the transmission loss (TL) of a system with resonators connected to the main duct and a side branch ...

impact of side-branch flow in coronary bifurcation intervention

background: the optimal strategy in percutaneous coronary intervention (pci) for coronary artery bifurcation lesions has yet to be agreed upon. we compared a strategy for stenting the main vessel to provide a complete perfusion flow in the side branch, namely thrombolysis in myocardial infarction (timi) - iii, with a strategy for intervention in both the main vessel and the side branch (mv + sb...

Flow Tones in a Pipeline-Cavity System: Effect of Pipe Asymmetry

Optimizing Circular Side-Resonators to Reduce Computer Fan Noise

One of the main noise sources in computers are the cooling fans. Tonal noise at the rotational frequency of the fan, the blade passing frequency (BPF) and its higher harmonics are important in fan noise. So called 'side-resonators' integrated in the duct of an in-duct axial fan cause an impedance change in the duct and, having proper dimensions and correct position, act as an acoustic mirror re...